Diploid-like meiotic behavior in synthesized amphiploids of the genus Glycine Willd. subgenus Glycine

1985 ◽  
Vol 27 (6) ◽  
pp. 655-660 ◽  
Author(s):  
R. J. Singh ◽  
T. Hymowitz
Keyword(s):  
Chromosomal Instability ◽  
Interspecific Hybrids ◽  
Meiotic Behavior ◽  
Preferential Pairing ◽  
Homologous Chromosomes ◽  
Tetraploid Hybrid

Six amphiploids consisting of one allotetraploid (2n = 4x = 80), four allohexaploids (2n = 6x = 120), and one allooctoploid (2n = 8x = 160) were synthesized by doubling the chromosomes of F1 interspecific hybrids of the following parents: one diploid (Glycine latifolia 2n = 2x = 40 × G. clandestina, short pod (Sp), 2n = 2x = 40); four triploids (G. clandestina, Sp, 2n = 2x = 40 × G. tabacina 2n = 4x = 80), (G. tabacina 2n = 4x = 80 × G. canescens 2n = 2x = 40), (G. tomentella2n = 4x = 80 × G. canescens 2n = 2x = 40 and its reciprocal); and one tetraploid (G. tomentella2n = 4x = 80 × G. tabacina 2n = 4x = 80). Chromosomal chimerism was observed in the C1 generation. Pod set was recorded in all the colchicine-treated hybrids except in the tetraploid hybrid of G. tomentella × G. tabacina. In C2 generation plants, chromosomal instability was noticed only in the allohexaploid of G. tabacina × G. canescens. All of the amphiploids showed diploid-like meiosis in the majority of the sporocytes and did not exhibit expected multivalent associations, a classical example of allopolyploidy. This was attributed to strong preferential pairing between homologous chromosomes which may be under genetic control.Key words: Glycine, synapsis, interspecific hybrids.

Secondary Tetrasomic Segregation of MDH-B and Preferential Pairing of Homeologues in Rainbow Trout

Genetics ◽  
1997 ◽  
Vol 145 (4) ◽  
pp. 1083-1092 ◽  
Author(s):  
Fred W Allendorf ◽  
Roy G Danzmann
Keyword(s):  
Allelic Variation ◽  
Male Meiosis ◽  
Proximal Region ◽  
Stage Model ◽  
Preferential Pairing ◽  
Homologous Chromosomes ◽  
Tetrasomic Inheritance ◽  
Segregation Ratios ◽  
Homeologous Chromosomes ◽  
Duplicated Loci

We examined the inheritance of allelic variation at an isozyme locus, MDH-B, duplicated by ancestral polyploidy in salmonid fishes. We detected only disomic segregation in females. Segregation ratios in males were best explained by a mixture of disomic and tetrasomic inheritance. We propose a two-stage model of pairing in male meiosis in which, first, homologous chromosomes pair and recombine in the proximal region of the chromosome. Next, homeologous chromosomes pair and recombine distally. We suggest that this type of tetrasomic inheritance in which centromeres segregate disomically should be referred to as “secondary tetrasomy” to distinguish it from tetrasomy involving entire chromosomes (i.e., “primary tetrasomy”). Differences in segregation ratios between males indicate differences between individuals in the amount of recombination between homeologous chromosomes. We also consider the implication of these results for estimation of allele frequencies at duplicated loci in salmonid populations.

scholarly journals Oligo-painting and GISH reveal meiotic chromosome biases and increased meiotic stability in synthetic allotetraploid Cucumis ×hytivus with dysploid parental karyotypes

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Qinzheng Zhao ◽  
Yunzhu Wang ◽  
Yunfei Bi ◽  
Yufei Zhai ◽  
Xiaqing Yu ◽  
...  
Keyword(s):  
Interspecific Hybridization ◽  
Interspecific Hybrids ◽  
Chromosome Doubling ◽  
Meiotic Chromosome ◽  
Genomic In Situ Hybridization ◽  
Meiotic Behavior ◽  
Cytological Evidence ◽  
Meiotic Stability ◽  
Inbred Family

Abstract Background Meiosis of newly formed allopolyploids frequently encounter perturbations induced by the merging of divergent and hybridizable genomes. However, to date, the meiotic properties of allopolyploids with dysploid parental karyotypes have not been studied in detail. The allotetraploid Cucumis ×hytivus (HHCC, 2n = 38) was obtained from interspecific hybridization between C. sativus (CC, 2n = 14) and C. hystrix (HH, 2n = 24) followed by chromosome doubling. The results of this study thus offer an excellent opportunity to explore the meiotic properties of allopolyploids with dysploid parental karyotypes. Results In this report, we describe the meiotic properties of five chromosomes (C5, C7, H1, H9 and H10) and two genomes in interspecific hybrids and C. ×hytivus (the 4th and 14th inbred family) through oligo-painting and genomic in situ hybridization (GISH). We show that 1) only two translocations carrying C5-oligo signals were detected on the chromosomes C2 and C4 of one 14th individual by the karyotyping of eight 4th and 36 14th plants based on C5- and C7-oligo painting, and possible cytological evidence was observed in meiosis of the 4th generation; 2) individual chromosome have biases for homoeologous pairing and univalent formation in F1 hybrids and allotetraploids; 3) extensive H-chromosome autosyndetic pairings (e.g., H-H, 25.5% PMCs) were observed in interspecific F1 hybrid, whereas no C-chromosome autosyndetic pairings were observed (e.g. C-C); 4) the meiotic properties of two subgenomes have significant biases in allotetraploids: H-subgenome exhibits higher univalent and chromosome lagging frequencies than C-subgenome; and 5) increased meiotic stability in the S14 generation compared with the S4 generation, including synchronous meiosis behavior, reduced incidents of univalent and chromosome lagging. Conclusions These results suggest that the meiotic behavior of two subgenomes has dramatic biases in response to interspecific hybridization and allopolyploidization, and the meiotic behavior harmony of subgenomes is a key subject of meiosis evolution in C. ×hytivus. This study helps to elucidate the meiotic properties and evolution of nascent allopolyploids with the dysploid parental karyotypes.

scholarly journals Meiotic analysis in induced tetraploids of Brachiaria decumbens Stapf

2011 ◽  
Vol 11 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Carine Simioni ◽  
Cacilda Borges do Valle
Keyword(s):  
Chromosome Segregation ◽  
Pollen Fertility ◽  
Interspecific Hybrids ◽  
Somatic Chromosome ◽  
Breeding Program ◽  
Meiotic Behavior ◽  
Brachiaria Decumbens ◽  
Meiotic Analysis ◽  
Chromosome Duplication

The meiotic behavior of three tetraploid plants (2n=4x=36) originated from somatic chromosome duplication of sexually reproducing diploid plants of Brachiaria decumbens was evaluated. All the analyzed plants presented abnormalities related to polyploidy, such as irregular chromosome segregation, leading to precocious chromosome migration to the poles and micronuclei during both meiotic divisions. However, the abnormalities observed did not compromise the meiotic products which were characterized by regular tetrads and satisfactory pollen fertility varying from 61.36 to 64.86%. Chromosomes paired mostly as bivalents in diakinesis but univalents to tetravalents were also observed. These studies contributed to the choice of compatible fertile sexual genitors to be crossed to natural tetraploid apomicts in the B. decumbens by identifying abnormalities and verifying pollen fertility. Intraespecific crosses should reduce sterility in the hybrids produced in the breeding program of Brachiaria, a problem observed with the interspecific hybrids produced so far.

Homozygous and heterozygous homologous chromosomes: effects on preferential pairing and recombination frequency in wheat

Genome ◽  
1988 ◽  
Vol 30 (3) ◽  
pp. 336-340 ◽  
Author(s):  
E. Y. Suárez ◽  
L. Gorgoschidse ◽  
F. Sacco ◽  
H. Saione
Keyword(s):  
Genetic Analysis ◽  
Recombination Frequency ◽  
Preferential Pairing ◽  
Homologous Chromosomes ◽  
Positive Correlation

Trisomics for chromosomes 1A and 6B of wheat backcrossed to euploids showed progeny with unexpected segregation frequencies (cytological and genetical) that can be attributed to preferential pairing between homologues. Recombination frequency between the centromere and a gene for mildew reaction of chromosome 1A showed an increase from the first to the second backcross that could be attributed to a positive correlation between homozygosity and the degree of pairing between homologous chromosomes. The use of wheat trisomics for genetic analysis is also discussed.Key words: preferential pairing, trisomic segregation, wheat cytogenetics, recombination frequency, pathogen reaction.

scholarly journals Aegilops × Secale hybrids: the production and cytology of diploid hybrids

1971 ◽  
Vol 17 (1) ◽  
pp. 17-31 ◽  
Author(s):  
B. N. Majisu ◽  
J. K. Jones
Keyword(s):  
Embryo Culture ◽  
Interspecific Hybrids ◽  
Diploid Species ◽  
Genetic Mechanism ◽  
Genetic Incompatibility ◽  
Homologous Chromosomes ◽  
Homoeologous Chromosomes

SUMMARYHybrids between four diploid species of Aegilops and species of Secale were obtained by using embryo culture. There was a marked incompatibility in the crosses between Secale species and each of the four species in Section Sitopsis of Aegilops and Ae. mutica. It is suggested that this genetic incompatibility with Secale species is an additional similarity between these species of Aegilops and the diploid species of Triticum.Most chromosomes of Aegilops (A) and Secale (S) are univalent during meta-anaphase of meiosis in these hybrids, but some appeared to associate and others to pair as apparently normal chiasmate bivalents. Analysis of non-chiasmate and chiasmate associations showed that the frequencies of autosyndetic (AA and SS) and allosyndetic (AS) associations fitted the 3AA: 7AS: 3SS ratio expected if association and pairing is at random. Any deviations from random involved a deficiency rather than an excess of Aegilops-Secale pairing. There is no evidence that the chromosomes of Secale are homologous with those of Ae. caudata, Ae. comosa and Ae. umbel-lulata, and it is suggested that the genome of Secale species does not show any homology with the genomes of the genera Aegilops. This does not preclude the presence of homologous segments. It is suggested that the possibility of random association of chromosomes should be considered when occasional pairing in interspecific hybrids is analysed, and that identification of chromosomes and recognition of chiasmata are required. The possibilities of chiasmata between non-homologous chromosomes, of a genetic mechanism in rye which suppresses the pairing of homoeologous chromosomes, and of other factors causing asynapsis and pseudo-synapsis between genetically similar chromosomes are discussed.

Meiotic behavior in interspecific hybrids between Brachiaria ruziziensis and Brachiaria brizantha (Poaceae)

Euphytica ◽  
2005 ◽  
Vol 145 (1-2) ◽  
pp. 155-159 ◽  
Author(s):  
Claudicéia Risso-Pascotto ◽  
Maria Suely Pagliarini ◽  
Cacilda Borges do Valle
Keyword(s):  
Interspecific Hybrids ◽  
Meiotic Behavior ◽  
Brachiaria Brizantha ◽  
Brachiaria Ruziziensis

Interspecific hybrids between a transgenic rapeseed (Brassica napus) and related species: cytogenetical characterization and detection of the transgene

Genome ◽  
1993 ◽  
Vol 36 (6) ◽  
pp. 1099-1106 ◽  
Author(s):  
M. C. Kerlan ◽  
A. M. Chevre ◽  
F. Eber
Keyword(s):  
Chromosome Pairing ◽  
Related Species ◽  
Interspecific Hybrids ◽  
Plant Production ◽  
Triploid Hybrid ◽  
Bar Gene ◽  
Meiotic Behavior ◽  
Gene Dispersal ◽  
Gene Characterization ◽  
Transgenic Rapeseed

In interspecific hybrids produced between a transgenic rapeseed, an allotetraploid species, resistant to herbicide, phosphinotricin, and five diploid related species, the risk for gene introgression in weed genomes was explored through cytogenetic and bar gene characterizations. Among the 75 hybrids studied, most had the expected triploid structure, with the exception of B. napus – B. oleracea amphidiploid plants and one B. napus – S. arvensis amphidiploid plant. In triploid hybrid plants, the reciprocal hybrids did not exhibit any difference in their meiotic behavior. The comparison of the percentage of chromosome pairing in the hybrids with that of haploid rapeseed permit to conclude that allosyndesis between AC genomes and related species genomes took place. This possibility of recombination was confirmed by the presence of multivalent associations in all the interspecific hybrids. Nevertheless, in B. napus – B. adpressa hybrids a control of chromosome pairing seemed to exist. The possibility of amphidiploid plant production directly obtained in the F1 generation increased the risk of gene dispersal. The B. napus – B. oleracea amphidiploid plant presented a meiotic behavior more regular than that of the B. napus – S. arvensis amphidiploid plant. Concerning the herbicide bar gene characterization, the presence of the gene detected by DNA amplification was correlated with herbicide resistance, except for two plants. Different hypotheses were proposed to explain these results. A classification of the diploid species was established regarding their gene dispersal risk based on the rate of allosyndesis between chromosomes of AC genomes of rapeseed and the genomes of the related species.Key words: Brassicaceae, transgenic rapeseed, risk assessment, interspecific hybrids, chromosome pairing, bar gene characterization.

PREFERENTIAL PAIRING OF CHROMOSOMES IN A TETRAPLOID HYBRID BETWEEN ORYZA GLABERRIMA AND O. SATIVA

1968 ◽  
Vol 10 (3) ◽  
pp. 527-535 ◽  
Author(s):  
Hiko-Ichi Oka
Keyword(s):  
Oryza Sativa ◽  
Oryza Sativa L ◽  
Oryza Glaberrima ◽  
Tetraploid Species ◽  
Preferential Pairing ◽  
Tetraploid Hybrid ◽  
Segregation Ratios ◽  
Gametic Selection ◽  
High Degree ◽  
Species Hybrids

A tetraploid hybrid was obtained from a cross between induced tetraploid strains of Oryza sativa L. and O. glaberrima Steud., which differed in glutinous (waxy) vs. non-glutinous starch (gl: +) and other genes. In the hybrid, as compared with the parental strains, there was a reduced number of quadricvalents and a relatively high degree of fertility. Segregation ratios for the glutinous gene observed in the back-cross and F2 generation appeared to be modified not only by preferential homogenetic pairing but also by gametic selection. Taking into account the effect of gametic selection estimated from simplex heterozygotes, it was suggested that preferential pairing could take place to a certain extent. It seems to be difficult to measure quantitatively the degree of preferential pairing in tetraploid species hybrids, unless the effect of various segregation-distorting factors can be accounted for.

HYBRIDIZATION BETWEEN ANNUAL AND PERENNIAL DIPLOID SPECIES OF HELIANTHUS

1978 ◽  
Vol 20 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Ernest D. P. Whelan
Keyword(s):  
Interspecific Hybrids ◽  
Diploid Species ◽  
Paracentric Inversion ◽  
Sterile Hybrid ◽  
Meiotic Behavior ◽  
Perennial Species ◽  
Annual Species ◽  
Normal Pollen

Hybrid characteristics, fertility and meiosis are described for the first interspecific hybrids to be obtained from crosses of the two perennial species (2n = 34) Helianthus giganteus and H. maximiliani with the annual species H. annuus (2n = 34). A single, highly pollen-sterile hybrid, H. giganteus × H. annuus cv. Krasnodarets, had abnormal meiosis with meiocytes containing univalents and multivalents. It was completely female sterile. The three H. giganteus × wild H. annus and four H. maximiliani × wild H. annuus hybrids had less than 5% normal pollen, and meiotic behavior suggested the presence of at least three interchanges and a paracentric inversion. Small quantities of seed were obtained by backcrossing with H. annuus cv. Saturn.

Cytogenetic analyses of intersectional hybrids between Parthenium argentatum and Parthenium confertum

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 134-140 ◽  
Author(s):  
A. Hashemi ◽  
A. Estilai ◽  
J. G. Waines
Keyword(s):  
Natural Rubber ◽  
Growth Habit ◽  
Backcross Progeny ◽  
Woody Species ◽  
Herbaceous Species ◽  
Parthenium Argentatum ◽  
Preferential Pairing ◽  
Homologous Chromosomes ◽  
Multivalent Formation ◽  
Cytogenetic Analyses

Induced tetraploid guayule (Parthenium argentatum Gray, a rubber-producing and woody species of section Parthenicaeta) was crossed to P. confertum var. lyratum Gray, a herbaceous species of section Argyrocheta. Hybrids were obtained when guayule was used as female. Like their diploid progenitors, induced tetraploids were sexual and self-incompatible. At meiosis, they averaged 0.30 I, 29.63 II, 0.12 III, and 3.02 IV. Parthenium confertum had 69 chromosomes and was apomictic. At meiosis, it averaged 1.00 I, 32.98 II, and 0.51 IV. Hybrids received 36 chromosomes from guayule and 34 chromosomes from P. confertum. At meiosis, they averaged 0.52 I, 33.44 II, 0.20 III, and 0.50 IV. F1 plants behaved like an amphidiploid in which homologous chromosomes of guayule genome paired with each other and homologous chromosomes of P. confertum genome also paired preferentially. Chromosome association in the hybrids indicated that P. confertum parent may be a tetraploid with suppressed multivalent formation. Although hybrids were partially fertile and produced backcross progeny, the transfer of desirable traits (rapid growth and herbaceous growth habit) from P. confertum into guayule will depend on elimination of preferential pairing in the hybrids.Key words: guayule, natural rubber, meiosis, chromosome pairing.

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